Abstract Detail

Estimating Paleotemperature at the Early Pliocene Gray Fossil Site (Eastern Tennessee, USA) from the Paleobotanical Record.

The Early Pliocene Gray Fossil Site in eastern Tennessee is described as a waterhole surrounded by a temperate forest dominated by Quercus and Carya. The geology plus the floral and faunal diversity have led to the hypothesis that during the Early Pliocene the region was warmer and wetter than present-day, however, this has never been quantified. Temperature and precipitation were estimated using leaf margin analysis (LMA) and climate leaf analysis multivariate program (CLAMP) based on 33 fossil leaf morphotypes recovered from GFS sediments. LMA predicts a mean annual temperature of 22.86 ° Celsius for the region, while CLAMP predicts 16.62° Celsius with an average annual precipitation of 122.28 centimeters. Estimates were then compared to modern averages in the region. While the CLAMP estimates for GFS are close to modern averages, the results from leaf margin analysis seemed abnormally high. It is probable that the average fell somewhere in between these two estimates. Based on experimental margins of errors for both methods, it is estimated that the climate at the Gray Fossil Site during the Early Pliocene (4.7 - 4.9 million years) would have been approximately 20° Celsius. Understanding the climate of the time permits a clearer interpretation of the mid-Appalachian region ecosystems responses to change.